Reconstruction of Articular Cartilage Defects with Free Periosteal Grafts: An Experimental Study

The chondrogenic potential of free autogenous periosteal grafts was studied histologically in 6-month-old rabbits. The grafts were taken from the tibia and transplanted to 7 × 14 mm large artificial defects of the femoral articular cartilage. The results revealed that the defects were repaired and filled after 4 weeks with a hyaline-like cartilage which was histologically similar to the cartilage adjacent to the transplant. The tissue maintained this morphology after 1 year of observation. In control animals where no periosteum was transplanted to the defect, no real cartilage was found. The tissue which partially filled the defect was a variable mixture of fibrous tissue and fibrocartilage.     

Evaluation of Neointimal Hyperplasia on Tranilast-Coated Synthetic Vascular Grafts: An Experimental Study

Tranilast is an antiallergic drug that interferes with proliferation and migration of vascular smooth muscle cell induced by platelet-derived growth factor (PDGF) and transforming growth factor-β1 (TGF-β1). We investigated the local effect of tranilast on neointimal hyperplasia using tranilast-coated prosthetic grafts. The inner sides of the thin-walled polytetrafluoroethylene (PTFE) grafts were coated with chitosan and tranilast containing chitosan solution. Wistar albino rats (32) were used in the study. Patches (1 × 2 mm) for vascular grafts were prepared. Three groups were tested: group 1 (n = 12; tranilast coated), group 2 (n = 10; adhesive-only film-layer–coated), and group 3 (n = 10; normal ePTFE patch grafts sutured to the carotid arteries of the rats). Recipient sites of the carotid arteries were excised 4 weeks after surgery. All sections were examined histologically for graft patency, thrombus formation, and neointimal thickness. Expression of PDGF, fibroblast growth factor, and TGF-β1 on cross-sections of the neointima were evaluated by immunohistochemistry. No significant differences were found regarding mean neointimal thicknesses. PDGF and TGF-β-1 expressions were significantly lower in group 1. Although a decrease in local effect of tranilast was observed for growth factor expressions at a drug concentration of 0.05 mg/cm², a significant reduction in neointimal hyperplasia was not achieved. The coating concentration of 0.05 mg/cm² may have been too low to produce an antiproliferative effect. Given our promising results, further studies are recommended and planned using different drug concentrations and time intervals.     

Machine Perfusion Preservation for Kidney Grafts With a High Creatinine From Uncontrolled Donation After Cardiac Death

Background

This study evaluated the usefulness of machine perfusion preservation parameters as selection criteria for donation after cardiac arrest (DCD) with high creatinine level. The aim of this study is to evaluate to whether DCD donor >50 years old and with high creatinine are acceptable.

Methods

We examined 17 kidneys from uncontrolled DCD who showed creatinine levels >3.0 mg/dL before procurement. The study included the following two groups: group 1 (n = 9), donor age <50 years old versus group 2 (n = 8), donor age >50 years old.

Results

There were no significant differences in donors or preservation conditions among the 2 groups, including age, terminal creatinine, warm ischemic time, cold perfusion time, and total ischemic time. A greater resistance of 47.9 mmHg/mL per min/g was observed among group 2, compared with 42.5 mmHg/mL per min/g in group 1. A shorter ATN period (8.2 days) was noted in group 1, compared with 21.2 days for group 2. The flow rate (mL/g/min) was not significantly different between the two groups. The best-Cr level was 1.22 mg/dL in group 1 and 1.94 mg/dL in group 2.

Conclusion

Machine perfusion flow was a reliable indicator of graft viability in uncontrolled DCD, particularly kidneys with high creatinine level. Even older donors were acceptable if the machine perfusion preservation parameters such as flow rate and pressure were acceptable; however, they may show severe delayed graft function.     

Preservation and function of heterologous aortic valves: An Experimental Study

Heterologous aortic valves are used in many clinics as replacements for diseased human aortic and mitral valves. These valves possess all the advantages of homologous aortic valves and are more easily available to the surgeon. The heterologous valve also provides a greater choice of valve size than does the homograft; this can be of importance when replacing the mitral valve. Heterograft valves, like homografts, are usually preserved for periods ranging from a few days to a few months before insertion into a patient. Four methods of preservation, described, are currently in use. This study compares the effects of these four methods of preservation when pig valves are transplanted into the dog's aorta.     

Luminescence-Based Assay to Screen Preservation Solutions for Optimal Ability to Maintain Viability of Rat Intestinal Grafts

Background

Segmental intestinal transplantations from living, genetically related donors provide advantages compared with those from cadaveric subjects. However, successful preservation during ischemic cold storage is critical for living donor grafts. Thus, the development of preservation solutions that maintain graft viability is essential for success. Herein we have reported application of a cell-based viability assay in multiwell plates to assess the effectiveness of various solutions to preserve intestinal grafts.

Methods

Freshly isolated intestinal chips from luciferase transgenic rats were placed in 96-well tissue culture plates for incubation at 4°C for 24 hours in various preservation solutions: ET-Kyoto (ET-K), University of Wisconsin (UW) solution, Euro-Collins (EC) solution, histidine-tryptophan-ketoglutarate (HTK) solution, lactated Ringer’s (LR) solution, or saline.

Results

As indicated by a higher level of luminescence, intestinal chips preserved in UW, HTK, or ET-K solution contained more viable cells, than those preserved in EC, LR, or saline solution. After exposure to the preservation solutions for 1 hour, the mucosal layer chips showed lower cell viability than the muscle layer chips.

Conclusion

Our data demonstrated that ET-K and UW solutions used together with intestinal chips of Luciferase transgenic rat and in vivo imaging provided optimal viability during ischemic cold storage prior to transplantation. Further development of preservation conditions to minimize the loss of viability of intestinal grafts before clinical transplantation is essential to improve outcomes.     

Comparison of Hybrid Vascular Grafts and Standard Grafts in Terms of Kidney Injury for the Treatment of Thoraco-Abdominal Aortic Aneurysm

World Journal of Surgery - We present a comparison of renal function outcomes during HTAR with the use of a new hybrid vascular graft (GHVG) or standard graft. It is a multicenter, retrospective,...     

Morphology and Function of Preserved Microvascular Arterial Grafts: An Experimental Study in Rats

n = 10) or in phosphate-buffered saline (PBS) (n= 10) for 1, 3, 7, and 14 days and were examined with light microscopy (LM) and scanning electron microscopy (SEM). Rat aortic preparations were stored in UW or PBS for 1 hour, 24 hours, 72 hours, 7 days, and 14 days and assessed for functional responses (stimulated contraction and endothelium-dependent relaxation). Segments (5 mm) of rat carotid arteries were stored in UW or PBS for 3 days, 7 days, and 14 days and orthotopically implanted as autografts and allografts. No immunosuppressive or anticoagulant agents were used. After 28 days of implantation, the grafts were assessed for patency and excised for LM and SEM. In UW, the endothelial layer remained intact up to 9 days of storage. In PBS, the endothelial layer showed deterioration after 1 day and was completely lost after 3 days. Functional responses were demonstrated to exist for as long as 7 days storage in UW. In PBS, no responses could be evoked after 24 hours storage. Autografts preserved in UW for 3 days (n= 6), 7 days (n= 6), and 14 days (n= 6) showed patency rates of 83.3%, 66.6%, and 66.6%, respectively, whereas patency rates of allografts were 66.6%, 33.3%, and 33.3%, respectively. Autografts stored in PBS for 3 days (n= 6), 7 days (n= 6), and 14 days (n= 6) showed patency rates of 33.3%, 33.3%, and 50%, respectively, whereas patency rates of allografts were 16.7%, 0%, and 33.3%, respectively. The UW preserved autografts showed normal morphology. All other groups showed vessel wall degeneration which in the allograft groups, were accompanied by lymphocellular infiltration. In conclusion, the endothelial layer and vessel wall of arteries are adequately preserved in UW. Functional responses are retained up to 14 days storage in UW, but, are lost after 24 hours storage in PBS. Autograft implantation studies accordingly show good performance of arterial segments preserved in UW, whereas allografts are subject to degradation as a result of rejection.     

Randomized Clinical Assay for Hepatic Grafts Preservation With University of Wisconsin or Histidine-Tryptophan-Ketoglutarate Solutions in Liver Transplantion

University of Wisconsin (UW) solution has been the standard for preservation of liver transplantation grafts since 1989. However, some studies demonstrated that histidine-tryptophan-ketoglutarate (HTK) solution is also effective. The purpose of this study was to compare the efficacy of both solutions in liver transplantation. From January 2003 to August 2004 the livers of deceased donors were randomized into HTK and UW groups. The 102 studied patients included 65 (63.7%) in the UW group and 37 (36.3%) in the HTK group. Sex, race, hemodynamic state, use of adrenergic drugs, and presence of steatosis in the donor were similarly distributed in the two groups (P > .05). The mean age of the donors was 38.1 years (SD ±14.4) in the UW group and 44.6 years (SD ±14.2) in the HTK cohort (P = .036). Sex, race, age, etiology of the cirrhosis, retransplant, acute liver failure, portal thrombosis, and Child-Pugh and MELD scores in the recipients were similarly distributed in the two recipient samples (P > .05). Among 89 patients who completed 4 months of follow-up, the HTK group included eight cases (25.8%) of biliary complications versus five cases (8.6%) in the UW group (P = .033; OR = 2.0 95% CI = 1.2-3.5). The incidence of graft dysfunction was 2.8% in the HTK group and 9.4% in the UW group (P = .15). In conclusion, UW and HTK solutions were equally effective for the preservation of the hepatic graft. The routine use of HTK solution can reduce the costs of liver transplantation.     

Radiologic and Histologic Assessment of Diced Cartilage Grafts for Cranial Bone Defects of Rabbits: An Experimental Study

This study was performed to experimentally evaluate the viability and coverage of diced cartilage grafts for cranial defects. Biparietal bone defects were prepared in each of 20 rabbits. Otogenous bone grafts were fixed to one side, whereas cartilage grafts taken from the right ear, diced, and wrapped with oxidized regenerated cellulose (Surgicel) were placed on other side. Parenchymal impression, contour, and ossification of all grafts in the 16 rabbits surviving after 8 weeks were evaluated with computed tomography and magnetic resonance imaging. The existence of ossification was examined pathologically. Parenchymal impression was significantly more frequent in bone grafts than in cartilage grafts (p < 0.05). This difference probably is attributable to the application technique. There was no significant radiographic difference in other parameters between the two groups. No significant difference in ossification was found. In conclusion, ossification was seen radiologically and pathologically in diced cartilage grafts. Because of autogenicity, ease of shaping, absence of postoperative warping, reduced resorption rates, and inherent viability and ossification properties, the authors suggest that diced cartilage grafts may be an alternative material for cranial defects, especially for frontal cranial reconstruction in which deformities may cause aesthetic and functional disabilities. The authors believe that further long-term studies also are needed.     

Preemptive Kidney Transplantation: Analysis of Kidney Grafts From the Same Donor

Background

From November 2003 to December 2012, in the Gdańsk Center, 64 patients received preemptive transplantation (PET). PET comprised 8% of 794 kidney transplantations performed during this time. The benefits for individual patients and for the health care system are discussed.

Methods

This study compares the outcomes of these PET patients who had their kidney pairs transplanted after a variable duration of dialysis (PTD), a total of 51 pairs.

Results

The mean Charlson comorbidity index was 2.57 vs 3.04 (P > .05) for the PET and PTD groups, respectively. Both groups did not differ significantly with respect to 1-year patient and graft survivals, and incidences of acute rejection. Five (9.8%) PET patients and 20 (39%) PTD patients experienced delayed graft function (P < .05). The graft function (serum creatinine/4p MDRD) 1 year after transplantation was similar in both groups (1.42/53.7 vs 1.43/57.4; mg/dL/mL/min/1.73 m²). More PET patients continued normal professional activities or education before and after transplantation (P < .05).

Conclusions

Our single-center results confirmed that for both medical and socioeconomic reasons, PET is an optimal mode of renal replacement therapy.     

Comparative Study of the Reconstruction of Articular Cartilage Defects with Free Costal Perichondrial Grafts and Free Tibial Periosteal Grafts: An Experimental Study on Rabbits

The purpose of this study was to compare the chondrogenic potential of free perichondrial with free periosteal grafts in the resurfacing of full-thickness defects of patellar articular cartilage in rabbits. We used adolescent New Zealand rabbits weighing between 2.4 and 3.6 kg. A 6-mm wide and 3-mm thick defect was created on the patellar articular surface. A total of 30 rabbits were randomly divided into a control group and two test groups. One test group received free perichondrial grafts (PC); the other received free periosteal grafts (PO). All the animals were killed 8 weeks after surgery. All the histological samples were scored from 0 to 17 according to a standard scoring system. Differences in the quality of the regenerated tissue were only found between the control and the test groups. There were no statistically significant histological differences between the grafted defects of the PC and the PO groups that there are not on any of the variables. The results of this study support that there are not significant differences in the quality of the repair tissue when using these two types of biological grafts. Received: 7 July 1998 / Accepted: 8 January 1999     

Reconstruction of Patellar Articular Cartilage with Free Autologous Perichondrial Grafts: An Experimental Study in Dogs

The cartilaginous potential of the perichondri-um has earlier been utilized to reconstruct articular cartilage in unloaded joints in adult rabbits. The present work in adult dogs has been performed to find out if the perichondrium can be used for the same purpose in joints subjected to pressure. In 13 knee joints the articular cartilage of the patella was excised completely and the resected surface was covered with an autologous perichon-drial graft taken from the rib cartilage. After 3 weeks of immobilization the dogs were allowed to run freely until sacrifice 2 to 17 months later. In all 13 cases regeneration of cartilage took place. Within 8 months the regenerated cartilage showed no or only very slight degenerative signs but from 12 months and later such changes were common. In control cases where the resected surface was left without any graft no cartilage at all was found. Conclusively cartilage formation from grafted rib perichondrium is achieved in the knee joints of adult dogs, but it does not resist considerable pressure forces.     

Preoxygenation of Different Preservation Solutions for Porcine Pancreas Preservation

Introduction

Organ preservation quality impacts porcine islet cell isolation and transplantation success. Among several preservation methods, the two-layer method is promising, but technically demanding and fails to deliver sufficient oxygen. The use of hyperbaric oxygenation may be an easier, more effective method to supply high partial pressure of oxygen (pO₂) for organ storage. Therefore, the aim of this study was to test the capability of preoxygenation of various preservation solutions with HBO to maintain high pO₂ levels.

Methods

University of Wisconsin (UW), Custodiol, Perfadex, or Celsior solutions were preoxygenated in a pressure chamber. NaCl served as the control. pO₂ levels were measured at defined times. The oxygen storage capability was evaluated by leaving the storage bottles open for 2 minutes.

Results

It was feasible to preoxygenate preservation solutions. The best solution to maintain high pO₂ tensions was Perfadex, followed by Celsior, and UW.

Discussion

The greater the amount of oxygen in the preservation solution, the more oxygen can be delivered to the preserved pancreas. Further studies on the influence of preoxygenated preservation solutions on the porcine pancreas are warranted to improve organ quality, porcine islet cell isolation, and transplantation success.